Prosthetic leg with a hydraulic knee control



May 2, 1967 LA VAUGHN MORTENSEN 3,316,558

PROSTHETIC LEG WITH A HYDRAULIC KNEE CONTROL Filed Nov. 12, 1-963INVENTOR L0 Vaughn L. Morfensen ATTORNEY United States Patent 3,316,558PROSTHETIC LEG WITH A HYDRAULIC KNEE CONTROL La Vaughn L. Mortensen, 616W. 107th St., Los Angeles, Calif. 90044 Filed Nov. 12, 1963, Ser. No.322,619 13 Claims. (Cl. 3-1.2)

This invention relates to artificial legs and more particularly to ameans for controlling the knee action of a leg prosthesis adapted to beused by above-the-knee amputees. This prosthesis may be used inconjunction with an independent articulated foot and ankle prosthesis.

Leg prostheses are often costly and complex and the motion effected bymany devices now in use is awkward and does not closely approximate anatural walking movement.

Many of the devices in use include variable controls which are needed byonly a small percentage of amputees. The prosthesis of this invention isof simple construction and there are no adjustments for its few movingparts. Thus, the unit may be preset at the factory.

It is an object of this invention to provide a light, simple andinexpensive leg prosthesis.

Another object of this invention is to provide a hydraulically operatedleg prosthesis which will enable an amputee to walk at a desired speedin a more natural manner.

It is a further object of this invention to provide a hydraulic kneecontrol for a leg prosthesis which may be used in conjunction with anindependent articulated foot and ankle prosthetic device.

A further object of this invention is to provide a knee control for aleg prosthesis which offers little resistance to the initial flexingmovement of the knee but increases resistance to the flexing motion asspeed and force of the movement increases.

Another object of this invention is to provide a knee control in a legprosthesis which will allow a rapid but controlled movement, with lessresistance during the extension cycle of the prosthetic leg movementthan during the flexing cycle.

Another object of this invention is to provide a hydraulie knee controlwhich is essentially tamper proof and has no need for periodicadjustments, since hydraulic action is consistent.

Since variable controls are needed by only a small percentage ofamputees, a further object of this invention is to provide a kneecontrol for a leg prosthesis which has no variable controls.

Further objects and advantages of this invention will become apparentfrom the following description referring to the accompanying drawing,and the features of novelty which characterize this invention will bepointed out with particularity in the claims appended to and forming apart of this specification.

In the drawing:

FIG. 1 is a sectional view of the knee control device of the presentinvention;

FIG. 2 is a sectional view of the knee control installed in a legprosthesis;

FIG. 3 is a rear view of the knee control installed in a leg prosthesis;and

FIG. 4 is a sectional View of the poppet valve used in conjunction withthe knee control device.

Numeral, 12 indicates a lower thigh portion of a leg prosthesis to whicha lower leg or shank member is hinged by a knee bolt 14.

The shank portion 20 and the thigh portion 12 pivot relative to eachother about knee bolt 14. Knee action is controlled by the knee controldevice of FIG. 1 which is indicated generally at 114 in FIG. 2.

A tubular member 116 is divided by a fixed partition 38 into an upperhydraulic cylinder 30 and a lower hydraulic cylinder 28. The partition38 is held in position by dimples 70. Fluid passages between cylinders28 and 30 are provided by poppet valve 40 and orifice 50. Floatingpiston 66 i disposed within cylinder 30, thus div-iding the cylinderinto chambers 32 and 34. O-ring 102 provides a seal between chambers 32and 34, thus preventing the passage of fluid from one chamber to theother.

Piston 60 is disposed within cylinder 28 and connected to piston rod 18which extends through a piston rod bearing 74. The piston rod bearing 74and O-rings 106 and 108 provide a fluid tight seal at the lower end oftubular member 116. The cylinder 28 is divided into chambers 62 and 64by piston 60. Fluid passage between chambers 62 and 64 is provided byorifice 58 which extends through piston rod 18, or which may be adaptedto pass through piston 60. The upper end of tubular member 116 is closedby cylinder head 10. A fluid tight seal is provided by O-ring 100.

The cylinder head 10 and the lower end 68 of piston rod 18 are eachprovided rubber or resilient members 24 into which bearings 26 arepressed.

Cylinder head 10 is pivotally attached to thigh member 12 rearwardly ofknee bolt 14 by means of pin. 16. Piston rod 18 is pivotally attached toshank portion 20 by means of pin 22. Resilient members 24 serve toretain the bearings 26 in such a manner as to prevent binding if shafts16 and 22 are not parallel with knee bolt 14 and to provide quieteraction.

Cylinder 28 and the lower chamber 32 of cylinder 30 are filled with ahydraulic fluid 36. Chamber 34 of cylinder 30 is partially filled withsaid hydraulic fluid and partially filled with a compressible fluid suchas air.

The poppet valve 40 disposed in partition 38 includes a casing 42 havingshoulders 44 and 45 thereon and being threaded as at 46 on its upperportion. The poppet valve is further composed of a valve stem 48 havingorifice 50 therethrough, a spring 52, a retainer collar 54 pressed onvalve stem 48, and avalve closing member 56. The poppet valve isnormally biased to a closed position by spring 52. If desired, orifice50 may pass through the partition 38 instead of poppet valve stem 48.

At the beginning of the knee flexing cycle the piston 60 is forcedupward into cylinder 28. This action causes hydraulic fluid 36 to beforced from chamber 64 into chambers 62 and 32 through orifices 58 and50. The poppet valve 40 which is biased to a closed position remainsclosed during the flexing cycle.

The size of orifice 50 regulates the flow of fluid from chamber 64 tochamber 32 to determine the resistance to the knee flexing motion. Themost desired action is obtained when orifice 50 is smaller than orifice58.

Fluid forced into chamber 32 urges floating piston 66 upwardly, thucompressing the compressible fluid such as air which partially fillschamber 34. The compressed fluid acts as a fluid spring, helps stop theflexing movement and serves to aid in the return of the prosthesis to anextended position. Momentum and gravity supply the remaining force toreturn the prosthesis to the extended position.

During the extension cycle the piston 60 moves down in cylinder 28, thusforcing the hydraulic fluid out of 3 chambers 62 and 32 and into chamber64. The reduced pressure in chamber 64 during the extension cycle causespoppet valve 50 to open, thus allowing little resistance to fluidmovement from chamber 32 to chamber 64. The

orifice 58 :thus controls the rate of fluid flow from chamber 62 tochamber ,64 and thereby controls the rate of travel of piston 60. Bycontrolling the travel of piston 60 orifice 58 also controls theresistance to the extension cycle of the prosthesis. It can be seen fromthe above that any change in the size of either one or both of theorifices '50 and58 may be made to regulate the knee action to to yieldto the relatively high pressure in chamber 32 during. the extensioncycle, thus allowing the valve gate 56 to move away from-casing 42 toopen the valve. At

the end of the extensioncycle the pressure in chamber 32 ceases to be.relatively greater than that in chamber 64- Thus, the valve stem and:gate are moved upward by spring 52 to close the valve. An importantfeature of this invention is the pivotal connection of the cylinder endof the pneumatic knee control device to the lower portion of thighmember 12. This makes possible the presence of hydraulic fluid 36 on'both sides of floating piston 66. This gives better lubrication andalso prevents the passageof compressible fluid from chamber 34 intoother chamlbers, as air in other chambers would tend to cause noise inthe mechanism. O-ring 102 provides a fluid seal for piston 66 and O-ring104 provides a fluid seal for piston 60.:

Rivet 110 is press fitted for holding head 10' in place,

and may be removed for servicing of chamber 34. Rivets 112 which arepress fitted and hold piston rod bearing 74 in place .may be removed tofacilitate service of the knee control device.

, While a particular embodiment of this invention has been illustratedand described, modifications thereof will It is to be understood,

occur to those skilled in the art. therefore, that this invention is notto be limited to the particular details disclosed, and it is intended inthe appended claims to cover all modifications within the spirit'andscope of this invention.

What is claimed is: I

1. In a leg prosthesis an upper thigh member, a lower shank member, ahinged connection of said members to 'form a knee joint, means tocontrol said knee joint, said.

means being comprised of a tubular member closed at one end and dividedby a fixed partition, a first cylinder and a second cylinder formed bysaid fixed partition,-a poppet valve in said partition, an orificethrough said poppet valve, aifloating piston in said first cylinder, apiston in said second cylinder, a piston rod connected to said piston insaid second cylinder, a piston rod bearing in the other'end of saidtubular-means through which said piston rod passes, a pivotal connectionbetween said thigh portion and said closed end of said tubular member,said pivotal connection located rearwardly of said knee joint, andapivotal connection betweensaid piston rod and said shank.

2. A claim according to claim 1 wherein said thigh member includes, astop along its lower portion, and said tubular member contacts said stopto terminate the exten- 4. A fluid chamber knee control device for a legprosthesis cmprising a tubular member closed at one end, a piston rodbearing in the other end through which a piston rod passes, a fixedpartition in said tubular member divid ing it into an upper and a lowercylinder, said partition having a poppet valve therethrough, an orificeconnecting said upper and lower cylinders, a floating piston in saidupper cylinder, a piston in said lower cylinder connected to said pistonrod, said floating piston dividing said upper cylinder into an upper anda lower chamber, the other said piston dividing the lower cylinder intoan upper and a lower chamber, means to prevent passage of fluid aroundsaid floating piston, means to prevent the passage of fluid around saidother piston, an orifice through said other piston to allow controlledpassage of fluid therethrough, and an orifice through said poppet valveto allow controlled passage of fluid therethrough.

5. A claim according to claim 4 wherein said lower cylinder and saidlower chamber of said upper cylinder are filled with hydraulic fluid andthe upper chamber of said upper cylinder is partially filled with saidhydraulic fluid, the remainder of said upper chamber of said uppercylinder being filled with a compressible fluid which acts as a fluidspring.

6. A leg prosthesis which includes an upper thigh member, a lower shankmember, a knee joint pivotally connecting said members, means forcontrol of said knee joint, said means comprising a tubular memberclosed at one end, a piston rod bearing through which a piston rodpasses sealing the other end, said closed end of said tubular memberbeing pivotally connected to said thigh member behind said knee joint,said piston rod being pivotally connected to said shank member, a fixedpartition in said tubular member dividing said tubular member into anupper and a lower cylinder, a poppet valve through said fixed partition,a floating piston in said upper cylinder dividing said cylinder intoupper and lower chambers, means to prevent the passage of fluid betweensaid chambers, a lower piston connected to said piston rod in .saidhydraulic fluid, the remaining portion of said upper chamber of saidupper cylinder containing a compressible fluid, an orifice through saidpoppet valve to allow controlled passage of fluid therethrou-gh, and anorifice through said lower piston to allow controlled passage of fluidtherethrough.

7. A leg prosthesis as described in claim 6 wherein said thigh memberincludes a stop along its lower portion, and said tubular member isadapted to contact said stop to terminate the extension movement of saidprosthesis.

8. A claim according to claim 7 wherein said stop is a resilient bumper.

9. A prosthesis according to claim 6 wherein said orifice in said pistonis relatively larger than said orifice in said poppet valve.

10. A leg prosthesis comprising an upper thigh member, a lower shankmember, a knee joint pivotally connecting said members, means pivotallyconnected between said members for control of said knee jointcomprising, a tubular member sealed at each end, a partition in saidtubular member, an upper cylinder and'a lower cylinder formed by saidpartition, hydraulic fluid in both said cylinders, a valve means joiningsaid cylinders, a nonvalve means. allowing continuous fluidcommunication between said cylinders, fluid spring means in said uppercylinder, a piston in said lower cylinder, an upper chamber and a lowerchamber in said lower cylinder formed by said piston, an orifice joiningsaid upper and lower chambers of said lower cylinder, and a piston rodconnected to said piston.

11. A claim according to claim 10 wherein one end of said tubular memberis pivotally attached to a thigh member of a leg prosthesis, and saidpiston rod is pivotally attached to a shank member of said legprosthesis.

12. A claim according to claim 11 wherein said thigh 5 member includes astop along its lower portion, and said tubular member contacts said stopto terminate the extension movement.

13. A leg prosthesis according to claim 10, wherein said valve means isa poppet valve disposed in said fixed partition, said poppet valvecomprising, a casing, a threaded portion on said casing, a valve stem,said valve stem extending through said casing, a passageway extendingthrough said valve stem, a shoulder on said casing, a collar on theupper part of said valve stem, a spring disposed 15 between saidshoulder and said collar and between said casing and said valve stem,and a valve gate disposed on the lower part of said valve stem, saidvalve gate normally being urged to a closed position by said spring.

References Cited by the Examiner UNITED STATES PATENTS 909,859 1/1909Apgar 3-2 X 2,489,291 11/ 1949 Henschke et al. 3-24 2,859,451 11/ 1958Mauch 322 3,147,966 9/1964 Axthamrner et al 26764 FOREIGN PATENTS316,515 12/1919 Germany.

31,662 12/ 1926 France.

(1st addition) 474,290 9/ 1952 Italy.

RICHARD A. GAUDET, Primary Examiner.

R. L. FRINKS, Assistant Examiner.

4. A FLUID CHAMBER KNEE CONTROL DEVICE FOR A LEG PROSTHESIS COMPRISING ATUBULAR MEMBER CLOSED AT ONE END, A PISTON ROD BEARING IN THE OTHER ENDTHROUGH WHICH A PISTON ROD PASSES, A FIXED PARTITION IN SAID TUBULARMEMBER DIVIDING IT INTO AN UPPER AND A LOWER CYLINDER, SAID PARTITIONHAVING A POPPET VALVE THERETHROUGH, AN ORIFICE CONNECTING SAID UPPER ANDLOWER CYLINDERS, A FLOATING PISTON IN SAID UPPER CYLINDER, A PISTON INSAID LOWER CYLINDER CONNECTED TO SAID PISTON ROD, SAID FLOATING PISTONDIVIDING SAID UPPER CYLINDER INTO AN UPPER AND A LOWER CHAMBER, THEOTHER SAID PISTON DIVIDING THE LOWER CYLINDER INTO AN UPPER AND A LOWERCHAMBER, MEANS TO PREVENT PASSAGE OF FLUID AROUND SAID FLOATING PISTON,MEANS TO PREVENT THE PASSAGE OF FLUID AROUND SAID OTHER PISTON, ANORIFICE THROUGH SAID OTHER PISTON TO ALLOW CONTROLLED PASSAGE OF FLUIDTHERETHROUGH, AND AN ORIFICE THROUGH SAID POPPET VALVE TO ALLOWCONTROLLED PASSAGE OF FLUID THERETHROUGH.
 10. A LEG PROSTHESISCOMPRISING AN UPPER THIGH MEMBER, A LOWER SHANK MEMBER, A KNEE JOINTPIVOTALLY CONNECTING SAID MEMBERS, MEANS PIVOTALLY CONNECTED BETWEENSAID MEMBERS FOR CONTROL OF SAID KNEE JOINT COMPRISING, A TUBULAR MEMBERSEALED AT EACH END, A PARTITION IN SAID TUBULAR MEMBER, AN UPPERCYLINDER AND A LOWER CYLINDER FORMED BY SAID PARTITION, HYDRAULIC FLUIDIN BOTH SAID CYLINDERS, A VALVE MEANS JOINING SAID CYLINDERS, A NONVALVEMEANS ALLOWING CONTINUOUS FLUID COMMUNICATION BETWEEN SAID CYLINDERS,FLUID SPRING MEANS IN SAID UPPER CYLINDER, A PISTON IN SAID LOWERCYLINDER, AN UPPER CHAMBER AND A LOWER CHAMBER IN SAID LOWER CYLINDERFORMED BY SAID PISTON, AN ORIFICE JOINING SAID UPPER AND LOWER CHAM-